Friday, January 20, 2012

When Did They Repeal Moore's Law?

Warning: this is a geeky post. If you have no interested in computers and technology, skip town.

You remember Moore's Law: According to Wikepedia, "Moore's law describes a long-term trend in the history of computing hardware: the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years. The period often quoted as "18 months" is due to David House, an Intel executive, who predicted that period for a doubling in chip performance (being a combination of the effect of more transistors and them being faster)."

This has led us to believe that computer speeds should double every 18 months or so.

I've been mucking about with the Lightroom 4 beta and, finding its performance wanting, started to question whether it's time to upgrade my home computer. I bought my home desktop just over 5 years ago and it is pretty much state-of-the-art for 2006. It has a quad-core cpu with 4 gb of memory. Over the years, I've added a nice graphics card and an SSD drive to speed things up. However, Lightroom performance is leisurely on my machine and I'd like to get back to that snappy feeling when you see the image change in real-time as you use Lightroom's adjustment sliders, not with a 1 or 2 second delay.

Given Moore's law, conservatively, a new computer should give performance of 8 times my old machine (i.e. performance should have double 3 times between 2006 and 2012).

My first stop was to look at Canada Computer for an inventory of parts needed to effect the upgrade. Here's what I decided to buy if I decided to buy (if you know what I mean):

A quad core Intel i7 cpu running at 3.4 gz, a pretty good step up in clock rate from my 2.4 gz cpu's and a huge leap forward to 2011 technology (32 nanometer chip) and moderately expensive at $334

A new motherboard to support the chip - an Asus board with high definition audio built in. This is surprisingly cheap at only $119.

(optionally) A second 128GB SSD drive to take my Lightroom catalog, preview files and cache for $120.

The total comes to around $600-$700 plus tax. Not cheap, but less costly than a new computer!

My next stop was Tom's Hardware to look at the relative performance of my current machine to my projected new machine. Here's a sample of what I found out:

There are more benchmarks, but this shows the general trend. For most benchmarks, the new i7 is just about double the speed of the old Q6600 chipset. There are a few exceptions, like the encryption benchmark, but it looks like I'm going to pay $600 for twice the performance of my current machine.

What happened to Moore's Law? A lot of the performance gain can be explained just with the difference in clock speed. The aggregate clock rate of my current chipset is 4x2.4=9.6. The aggregate clock speed of the new i7 chipset is 4x3.4=13.6. This is about a 40% uptick in clock rate. All the other stuff invented over the last 6 years (larger on-chip cache, pre-fetching algorithms, 2 threads per core, turbo mode overclocking, 32nm process) accounts for the other 60% of the performance improvement.

Based on this, I think we can declare that Moore's Law no longer applies to the desktop computer market. We are in the era of diminishing returns.

The other interesting tidbit that I found out, speaking of diminishing returns, is that you really don't get much of a bang for your buck if you buy a six processor chipset. Going back to Canada Computers, you can buy an Intel i7 980 with 6 cores for $630, nearly double the four core chipset. The motherboard needed is an LGA1366 type and it costs just about double the one needed for four cores.

What do you get for another $400? If you're interested, the results are here. The results are marginal at best, nowhere near the expected 33% improvement, showing that either software is generally not ready to leverage the additional 2 cores or that there is a lot of additional overhead involved in managing 6 cores.

So this leaves me wondering. Is it really worth $600 hard-earned dollars to double the speed of the home computer. This is a computer that still runs like a scalded cat for every application on it except Adobe Lightroom. Maybe it's time to think about another brand of raw conversion software instead since we're just about to be hit by a $200 upgrade cost for Lightroom 4. That $200 just might go to Phase One instead. Just thinking out loud here.